1. Field of the Invention
The present invention relates to an internet telephone system for achieving the functions of an internet telephone.
2. Related Art
In recent years, internet terminals capable of transmitting and receiving data over the Internet have become widespread. This type of internet terminal includes internet calling functions for executing a voice call by inputting and outputting voice signals via the Internet and inputting and outputting voice sounds based on such voice signals via a transceiver connected to the internet terminal. Examples of the transceiver include a handset that integrally combines a headphone or earphone with a microphone.
Voice sound based on voice signals inputted and outputted via the Internet can be inputted and outputted via a microphone and a speaker provided in the internet terminal. Depending on the installation positions of the microphone and speaker, however, voice sound outputted from the speaker may be difficult to understand and the volume of voice sound inputted via the microphone may be too low, resulting in an unsatisfactory voice call. Therefore, as disclosed in Japanese unexamined patent application publication No. 2001-86209, for example, a transceiver connected to the internet terminal is generally employed when using the internet calling functions.
However, since this transceiver is a special device for using the internet calling functions, the transceiver cannot be used for purposes other than using the internet calling functions.
It is conceivable to use, as a device functioning as the transceiver, a common telephone terminal that achieves voice calls by inputting and outputting voice sound through a handset based on voice signals transmitted via a telephone line network. When not using the internet calling functions, this type of telephone terminal can be used as an ordinary telephone terminal. In this case, there is no need to prepare a special device only for using the internet calling functions.
However, using a common telephone terminal in this manner raises a problem that a notification of an incoming call is not given on the telephone terminal end if the incoming call is received while the telephone terminal is disconnected from the internet terminal. Because a user on the telephone terminal end will not notice the incoming internet call in this case, the user cannot answer the incoming call and in some cases cannot even learn that there was an incoming call.